Modern petroleum drilling and production operations demand a great quantity of information relating to the parameters and conditions downhole. Such information typically includes the location and orientation of the borehole and drilling assembly, earth formation properties, and parameters of the downhole drilling environment. The collection of information relating to formation properties and downhole conditions is commonly referred to as “logging,” and can be performed using wireline logging tools or during the drilling process itself (hence the term “logging while drilling” or “LWD,” frequently used interchangeably with the term “measurement while drilling” or “MWD”). Information may also be collected using sensors embedded within the cement that secures the casing of a completed well to a borehole.
Because of the harsh environment present downhole, it can be challenging to design logging sensors and tools that operate reliably for extended periods of time within a borehole. This is particularly true for tools that include active electronic components to measure, amplify, sample and process signals present in the surrounding formation. Failures of such components can result in expensive delays in drilling (in the LWD case) or delays in logging (in the wireline logging case) while a tool is repaired or replaced, or in a reduction in monitoring capabilities for completed wells where the sensors generally cannot be accessed to be repaired or replaced. Increasing the reliability of logging tools and sensors is thus highly desirable.
It should be understood that the drawings and corresponding detailed description do not limit the disclosure, but on the contrary, they provide the foundation for understanding all modifications, equivalents, and alternatives falling within the scope of the appended claims.